1. Field of the Invention
The present invention relates to an apparatus employing a nonradiative dielectric line and, more particularly, to an apparatus suitable for an integrated circuit for use in a millimetric-wave band or a microwave band.
2. Description of the Related Art
FIGS. 26(A), 26(B) and 26(C) are sectional views illustrating the constructions of three types of a conventional nonradiative dielectric line (an NRD wave guide). FIG. 26(A) shows what is commonly called a normal-type nonradiative dielectric line in which a dielectric strip 100 is disposed between conductors 101 and 102 disposed substantially parallel to each other. FIG. 26(B) shows what is commonly called a grooved-type nonradiative dielectric line in which a groove is formed in each of the conductors 101 and 102, and the dielectric strip 100 is fitted into the grooves. FIG. 26(C) shows what is commonly called a winged-type nonradiative dielectric line comprising conductors 101 and 102 which contact plane-shaped wing portions 103' and 104' of dielectric strips 103 and 104, the dielectric strips 103 and 104 face each other across a gap.
In such a nonradiative dielectric line, transmission loss is reduced by making the spacing y between the conductors to be a half-wavelength of the propagation wavelength of the electromagnetic wave, thus suppressing radiation at a bent portion or a noncontinuous portion.
FIG. 27 shows an example of a conventional apparatus employing such a nonradiative dielectric line. Referring to FIG. 27, reference numeral 105 denotes a circuit board on which electrodes 106 and 107 are formed and a beam-lead diode 108 is mounted. With such a placement of a circuit board having electrodes formed thereon and having electronic parts mounted thereon on the end surface of the dielectric strip 100, in this example, the beam-lead diode 108 will be coupled to the electromagnetic wave which is propagated through the dielectric strip 100.
FIG. 28 shows an example in which a nonradiative dielectric line is applied to a Gunn oscillator. Referring to FIG. 28, reference numeral 109 denotes a strip line formed on the circuit board 105. Reference numeral 110 denotes a Gunn diode incorporated into the block, with its electrodes being connected to the strip line 109. The circuit board 105, being positioned in parallel to the end surface of the dielectric strip 100 (in a direction perpendicular to a direction parallel to the length of the dielectric strip), causes the electromagnetic wave propagated through the dielectric strip 100 and the strip line 109 to be electromagnetically coupled to each other.
As described above, in the conventional apparatus employing a nonradiative dielectric line, in order to couple a dielectric strip to a conductor line on a circuit board, a circuit board is positioned on the end surface of the dielectric strip, and the circuit board is positioned perpendicular to the length of the dielectric strip. However, in such a construction, it is difficult to fixedly secure the circuit board within the apparatus, and since the circuit board is likely to be inclined, the circuit board cannot be easily mounted. Further, since in this construction which a circuit board is disposed between two conductors, only long, narrow strip-shaped circuit boards can be used, and the patterns of conductor lines or the like that can be formed are limited. For this reason, it is not possible to form an integrated circuit of a relatively large-scale circuit with a small number of parts.
Further, with the dielectric strip being disposed between the conductors and an integrated circuit is formed together with the circuit board, adjustments cannot be performed with a single circuit board. Therefore, adjustment operations must be repeatedly performed. For example, characteristics are measured with the circuit board incorporated into the nonradiative dielectric line, the circuit board is removed during the adjustment, and the circuit board is assembled again after the adjustment and its characteristics are again measured. Thus, the adjustment operations are complicated and inefficient.